This paper describes functions of the components of hearing aids and provides a detailed procedure to detect hearing aid dysfunctions. The most common type of hearing aids for school children are the behind the ear type. Various hearing aid components change sound into an electrical signal, which is amplified and adjusted by a volume control. The resulting sound is then conducted through a receiver. The ear mold couples the hearing aid to the ear and directs the amplified sound into the ear's external canal. Power is supplied by a 1.3 or 1.5 battery. Malfunction can occur in any of the components. The problem is exacerbated when many school children hesitate to bring problems to anyone's attention. A hearing aid monitoring program would alleviate problems due to malfunctions and would meet the mandates set forth in Public Law 94-142, which ensures the proper functioning of hearing aids of school children. The best time to check hearing aids is just before or after lunch. A detailed hearing check procedure should be followed. Proper fit helps to assure that the child will not lose the hearing aid. Appendices include diagrams of various types of hearing aids, ear molds, and a hearing aid stethoscope and voltmeter used in hearing aid checks. (LP)